Researchers recover europium from fluorescent lamps
Scientists at the Swiss Federal Institute of Technology (Eidgenössische Technische Hochschule – ETH) in Zurich want to bring rare earths from old fluorescent lamps back into the cycle and have found a separation technique for the metal europium. Until now, the extraction and purification of rare earths has been expensive, time-consuming and harmful to the environment. They are hardly ever reused in Europe. In a feasibility study published in the journal Nature Communications, the scientists show that at least 50 times more europium can be recovered in just a few steps than with previous separation methods.
Inspired by nature
The key to this technique lies in small inorganic molecules featuring four sulphur atoms around tungsten or molybdenum: tetrathiometallates. This was inspired by the world of proteins: The molecules often occur as binding sites for metals in natural enzymes and serve as active agents against cancer and disorders of copper metabolism. This binding property is now being utilised for the separation of metals from the rare earth group.
The procedure comes at the right time: since 2023, fluorescent lamps may no longer be placed on the market in the European Union. Lighting systems will therefore have to be refurbished in the foreseeable future and large quantities of electronic waste will be generated because millions of fluorescent lamps are in circulation. The technology has already been patented. The researchers now want to extend the new separation process to other rare earth metals – such as neodymium and dysprosium from magnets. The university plans to found a start-up to commercialise the technology.